The present invention relates to a vibratory parts feeding machine capable of automatically feeding discrete chip electronic parts or other parts efficiently and continuously at a high speed.
While the vibratory parts feeding machine is widely used for automatically aligning and feeding discrete chip electronic parts such as chip resistors and chip capacitors, some parts need to be aligned not only in the orientation with respect to the shape but also in up/down direction of the face. For example, a part 1 (chip resistor) shown in FIG. 29 is a white ceramic substrate of rectangular shape having an electrode provided on either end in the longitudinal direction and a black resistor element formed on one of the faces (the face on which the resistor element is formed will be called the front face 1a, and the opposite face the back face 1b hereafter). Longitudinal dimension L, transverse dimension (width) D, vertical dimension (thickness) T, and ratios of these dimensions of the part 1 vary for different identification codes of the part. There are parts of diverse ranges of dimensions and shapes, for example, from sheet-like parts having large width to thickness (D/T) ratios to block-like parts having small width to thickness (D/T) ratios. As a parts front and back face aligning apparatus used in aligning such parts 1 in the up/down facing orientation, a configuration disclosed in Japanese Examined Patent Publication No.H1-34894, for example, is known.
In the parts front and back face aligning apparatus disclosed in the patent publication mentioned above, sheet-shaped parts are guided successively onto one of inclined surfaces of a V-shaped track, and each part is checked by parts front/back face sensing means to see whether the part is facing up or down. When the part is found to be facing down, the part is immediately turned over to the other inclined surface of the V-shaped track by parts turn-over means, for example an air jet device.
Operations from the determination of up-down direction and turning over of the part 1 are carried out on the same V-shaped track 30 in the apparatus of the prior art described above, as shown in FIG. 30. As a result, a force to move the part 1 (horizontal movement a1, vertical movement b1 of the center of mass of the part 1) is required in addition to the force to turn the part 1 in the process of turning over the part 1. Also a point S1 around which the part 1 is turned over moves by sliding along the inclined surface of the V-shaped track 30 thus giving rise to a frictional force. As a consequence, the operation of turning over the part 1 tends to be unstable, which becomes more conspicuous as the width to thickness (D/T) ratio of the part 1 becomes smaller.
Specifically, when the width to thickness (D/T) ratio of the part 1 becomes smaller, horizontal movement of the center of mass of the part 1 decreases (a2) and the vertical movement increases (b2), as shown in FIG. 31, thus making it necessary to exert a force for flipping the part 1 more upward. In case the force to turn over the part is insufficient, the part 1 only momentarily lifts and returns to the former position without turning over. When the force to turn over the part is excessive, on the other hand, the part 1 may be scattered without turning over. Also when the width to thickness (D/T) ratio of the part 1 becomes smaller, sliding movement of a support point S2 around which the part 1 is turned over increases resulting in increasing factors of instability in the series of turning over actions, thus making one factor of decreasing the efficiency of turning over.
An object of the invention is to increase the efficiency of turning over parts and increase the efficiency of feeding the parts, while making it possible to accurately aligning and feeding more diversified parts.
In order to achieve the object described above, the present invention provides a parts front and back face aligning apparatus for a vibratory parts feeding machine that feeds parts while carrying the parts along a track by means of vibration and aligning the orientation of the parts, and has a part front/back orientation correcting section comprising a first track for carrying the parts that have been guided from a track in the upstream in single row and single layer, parts front/back face sensing means for determining whether the part being carried on the first track faces up or down, parts turn-over means that exerts a force to turn over the part located on the first track according to the decision of the parts front/back face sensing means, and a second track to which the part that has been turned over by the parts turn-over means is transferred and carried thereon.
With the configuration described above, the turn-over operation when the part is transferred from the first track to the second track can be carried out with the border between the tracks serving as the support point around which the part is turned. The support point around which the part is turned preferably remains fixed.
The first track in the parts front/back orientation correcting section may have such a configuration that has a first inclined wall whereon the parts are carried in an inclined attitude and a second inclined wall that is inclined in the opposite direction to the first inclined wall. The second track may have such a configuration that has a third inclined wall whereon the parts that have been transferred thereon from the first track are carried in an attitude inclined in the direction opposite to that of the first inclined wall and a fourth inclined wall that is inclined in the opposite direction to the third inclined wall. It is preferable that the second inclined wall of the first track and the fourth inclined wall of the second track share a common apex. In this case, the part is turned over on and around the apex that serves as a fixed support point. The apex is preferably located below a locus along which the center of mass of the part moves while the part is being turned over, in order to carry out the turn-over operation smoothly.
A junction may be provided downstream of the parts front/back orientation correcting means, in order to cause the parts carried on the first track and the parts carried on the second track to join in the same attitude at the junction. Further, a merging section may be provided between the parts front/back orientation correcting means and the junction, in order to merge the parts carried on the first track and the parts carried on the second track onto one track.
In case the parts need not to be aligned in the up-down facing orientation, or it is not necessary to align all parts in the up-down facing orientation for such a reason as the number of parts to be fed to the next process is small although the parts would be aligned in the up-down facing orientation or there is imbalance between the probabilities of the parts to face up and face down due to the characteristics of the parts, such a configuration may be employed as all parts on the first track are turned over by the parts turn-over means without checking the parts to see whether the part faces up or down. The parts turn-over device may be used as preprocessing means in the upstream of the parts front and back face aligning apparatus.
According to the present invention, the following effects can be obtained.
(1) Higher efficiency of turning over the parts and higher efficiency of feeding the parts than the configuration of the prior art can be achieved.
(2) Broader range of parts can be aligned and fed, because high efficiency of turning over can be achieved for rectangular parts of width to thickness ratios near 1 and round parts of height to diameter ratios near 1.
(3) Parts can be aligned continuously at a high speed because the parts are aligned while being carried.